The present invention relates to a slider tester, which tests reading and writing functions of a slider (a magnetic head) for reading data from and writing data on a recording medium.
The slider for reading data from and writing data on a recording medium, e.g., a magnetic disk, is tested, then it is actually assembled in, for example, a magnetic disk drive unit. In the test, the recording medium is rotated, and floating characteristics and recording and writing functions of the slider are checked. In the conventional function test of the slider, a slider unit including the slider and a suspension, on which the slider is mounted, is assembled, then the slider unit is set in the slider tester so as to execute the function test. In the conventional slider tester, the recording medium is rotated so as to float the magnetic head therefrom, and a floating distance and the reading and writing functions of the slider are checked, so that the slider is judged if it is a good slider or a bad slider. The bad slider is scrapped together with the suspension.
Note that, in the present specification, the word “float” means the action of the slider moving away from a surface of the recording medium. Namely, the slider may be moved not only upwards with respect to the surface of the recording medium but also downwards and sidewards.
If the rate of producing bad sliders is high, many sliders are scrapped together with suspensions, so wasteful costs, e.g., costs of manufacturing sliders and suspensions and assembling slider units, are compounded. In the magnetic head for accessing a recording medium having a large capacity, the suspension has high functions and additional values. Therefore, the cost of manufacturing the suspension cannot be ignored. Further, the functions of the slider must be higher with increasing th capacity of the recording medium; high manufacturing technology is required, but yield of manufacturing sliders must be lower. Namely, the number of scrapped slider units and the wasteful costs are increased.
To solve this disadvantage, a method of testing the slider, in which the slider alone is tested before assembling the slider unit and only the good slider is mounted onto the suspension, is proposed. In the case of testing the, slider only, a recording medium is rotated and the slider is floated therefrom so as to check the floating distance and the reading and writing functions as well as the slider mounted on the suspension.
A lifting force of air, which is generated by rotating the recording medium, lifts or floats the slider from the recording medium; the suspension applies a pressing force, which is balanced with the lifting force, to the slider. Therefore, the floating distance of several tens nm from the recording medium can be maintained.
Namely, the slider tester must support the slider without obstructing the lifting force and apply the fixed pressing force to the slider. The slider must be easily set into and taken out from the slider tester before and after the test. The slider in a floating state must be electrically connected to a testing device.